Hepta- is a combining form used like a prefix meaning “seven.” It is used in a number of scientific and other technical terms. In chemistry, hepta- is specifically used to indicate seven atoms or seven groups of atoms in compounds, e.g., heptachlor.

Does hexa mean 6?

Hexa- is a combining form used like a prefix meaning “six.” It is used in a great many scientific and other technical terms.

What is meant by Heptahydrate?

: a compound with seven molecules of water.